Steady State Drug Levels describe equilibrium concentration reached with repeated dosing when drug input equals elimination. Definition of Steady-State Drug Levels: Steady state (Css) is reached when the rate of drug administration = rate of drug elimination. Occurs after ~4-5 half-lives of continuous dosing. Why It Matters Maintains consistent therapeutic levels Minimizes risk of toxicity … Read more
Multicompartment Models in Pharmacokinetics explain complex drug distribution and elimination across central and peripheral compartments. The body is often not homogeneous; after administration, a drug may distribute at different rates to different tissues. Multicompartment models are used to better describe drug distribution and elimination when it doesn’t fit simple one-compartment models. Definition of Multicompartment Models … Read more
Kinetics of Multiple Dosing explains drug accumulation, steady state concentration, and dosing intervals in pharmacokinetics. Kinetics of Multiple Dosing When drugs are given at regular intervals (e.g., every 8 hours), the drug accumulates in the body until a steady state is reached. Key Concepts: Accumulation: Occurs when drug is administered before previous doses are fully … Read more
Two-Compartment Open Model The two-compartment open model is a pharmacokinetic model used to describe how drugs distribute and eliminate within the body. This model divides the body into two theoretical compartments: Central Compartment Represents the blood and highly perfused organs (e.g., heart, liver, kidneys). Site of drug administration and elimination. Peripheral Compartment Represents less perfused … Read more
Two Compartment Open Model IV Bolus describes rapid drug distribution into central and peripheral compartments with elimination kinetics. Drug is administered rapidly into the central compartment. Distribution occurs between central and peripheral compartments. Elimination happens only from the central compartment. This model describes the pharmacokinetics of a drug administered intravenously in a single dose, where … Read more
Pharmaceutical powders can be categorized as either simple or compound powders. The differences between them are outlined in the table below: Feature Simple Powder Compound Powder Composition Contains a single active pharmaceutical ingredient (API). Contains two or more active pharmaceutical ingredients (APIs) in a specific ratio. Therapeutic Effect Exerts a single therapeutic effect due to … Read more
Mixing powders is a critical process in preparing pharmaceutical products like tablets, capsules, and bulk powders. The goal is to create a homogenous blend of active ingredients and excipients for consistent dosing. Powder mixing can be done through manual or mechanical 1. Manual Mixing Manual mixing uses simple tools like spatulas, mortars, and pestles to … Read more
An Isotonic Solutions has the same osmotic pressure as body fluids, preventing cell damage by maintaining balance between fluids. Isotonicity and Freezing Point Depression Isotonic solutions match the freezing point depression of body fluids, around -0.52°C. Example: 9 Isotonicity and Molecular Weight The osmotic pressure depends on the number of particles, not their mass. Formula … Read more
Methods of Drug Elimination include renal excretion, biliary excretion, pulmonary excretion, and metabolism for drug clearance. Methods of Drug Elimination Elimination is the process by which drugs are removed from the body. It primarily occurs through metabolism and excretion, ensuring that the drug’s effects do not persist indefinitely. Various pathways contribute to drug elimination, each … Read more
Pharmacokinetic Parameters include clearance, volume of distribution, half life, and bioavailability guiding drug dosing and therapy. Pharmacokinetics involves the study of how a drug is absorbed, distributed, metabolized, and eliminated by the body. The following are key parameters used to describe and quantify these processes: ke (Elimination Rate Constant) The elimination rate constant (ke) quantifies … Read more
